1. Field of the Invention
The invention relates to an ultrasonic flow rate measuring device, especially a clamp-on ultrasonic flow rate measuring device, for measuring the flow rate through a line through which a medium flows, with at least one ultrasonic transducer.
2. Description of Related Art
Clamp-on ultrasonic flow rate measuring devices are characterized in that they can be used especially easily. In contrast to other ultrasonic flow rate measuring devices which must be permanently integrated into the existing pipeline system by the device replacing a piece of the pipeline, clamp-on flow rate measuring devices can simply be placed from the outside on a suitable line section of the piping system. The line section to which the clamp-on ultrasonic flow rate measuring device is attached thus becomes more or less a measuring line without the need for its own separate measuring line which must be inserted into the piping system with great effort. This makes the use of clamp-on ultrasonic flow rate measuring devices simple and economical.
However, the problem in clamp-on ultrasonic flow rate measuring devices, as in other ultrasonic flow rate measuring devices, is often that the attainable signals are only very small. This can be attributed, for example, to low operating voltages due to the circuits which are made inherently safe. Moreover, the signal-to-noise ratio is also degraded by unmatched acoustic transitions between different materials. Finally, on the signal path, signal losses due to attenuation effects occur in the respective medium. This is often associated with a very small measurement signal which is output by the receiving ultrasonic transducer. Such a small measurement signal is, at this point, especially susceptible to electromagnetic noise.